Pushing the limits of nanopore transport performance by polymer functionalization

Abstract

Inspired by the design and performance of biological pores, polymer functionalization of nanopores has emerged as an evolving field to advance transport performance within the last few years.

Recent developments in visible light induced polymerization towards its application to nanopores

“…the increasing number of reported visible light induced polymerizations. [1][2][3] Polymer functionalized nanopores, for example, allow for specific control of molecular transport which is relevant in separation, energy conversion, sensing, or release. 2,[4][5][6][7][8][9][10] Especially, gating of molecular transport using stimuli-responsive polymers in nanopores has been demonstrated for all possible stimuli from pH, ion interaction to redox or even magnetic gating.…”

“…Such asymmetric design of porous materials has been shown to result in Janus materials for side selective separation or increased transport performance. 3,12 For example, theoretical studies from Huang and Szleifer demonstrated the relevance of controlled and local nanopore functionalization, as well as polymer sequence design of nanopores allowing transport direction. 13,14 An experimental implementation of local polymer functionalization including polymer sequence design has to be based on controlled (living) polymerizations.…”

“…33,36,37 Data driven material design needs large data and sample sets as shown for data driven nanopore application in the context of sensing. 3,38 Thus, automated synthesis is essential and of potentially increasing importance in future. This renders visible light induced polymerization with a potential for automated process design interesting.…”

Visible light induced RAFT for asymmetric functionalization of silica mesopores

“…9 Furthermore, high ionic rectification factors above 1000 for asymmetric designed nanopores have been theoretically demonstrated 10 by implementing two orthogonal gates at both entrances of a nanopore. 10 Although controlled polymer functionalization of nanopores significantly advanced within the last years, 1,2,11 experimental examples on local polymer placement and sequence control remain a challenge and need local polymer placement and controlled polymerization. Polymerization control in nanopores is most often achieved by surface-initiated atom transfer radical polymerization (SI-ATRP), SI-RAFT, or iniferter-initiated polymerizations.…”

“…Despite the numerous examples of gated nanopore transport, transport direction as well as selectivity is still a challenge in technological pores. 1,2 To date, directional transport has been experimentally demonstrated in Janus materials. [3][4][5][6] With respect to individual nanopores transport direction and ion rectication has been shown for asymmetrically shaped nanoscale pores and channels.…”